The invention relates generally to an apparatus and method for providing users in a digital broadcast system with on-demand access to encrypted content that is stored locally at user receivers or is transmitted via said digital broadcast system, and with the ability to decrypt and subsequently store the content on portable storage media.
Satellite digital audio radio service (SDARS), a satellite broadcast service established by the U.S. Federal Communications Commission (FCC), has been proposed using satellite transmission of digital audio programs to radio receivers. The radio receivers can be stationary receivers (i.e., with a receiver antenna pointed for optimal line of sight (LOS) reception from a satellite) or mobile receivers (e.g., a receiver that is hand-carried by a user or is mounted in a vehicle).
The type of content which can be distributed in an SDARS system or a similar digital broadcast system typically includes audio programs such as music recordings, advertisements, news programs and talk shows, among other audio programs, and data files. A significant amount of the content that is to be broadcast is predetermined prior to transmission such as popular songs. Radio stations, for example, frequently use play lists to determine how often a selected number of songs, which are identified as being most popular at a given point in time, are to be broadcast. Popular songs and other programs which can be repeated on a broadcast channel are in contrast to xe2x80x9clivexe2x80x9d commentary provided by a broadcast channel host, talk show host or other commentator, for example. Since bandwidth in a digital broadcast system is limited and valuable, efficient use of the bandwidth is desirable. A need therefore exists for a digital broadcast system wherein content is provided in a broadcast signal in an optimal manner to use bandwidth as efficiently as possible.
In addition, much of the content broadcast via a digital broadcast system is not available for purchase in conventional retail outlets. A need therefore also exists for a digital broadcast system which enables users to receive, purchase and store selected content in a broadcast data stream onto a personal storage device (e.g., a portable storage medium such as a compact disc, a digital audio tape (DAT) and the like). Accordingly, a need also exists for a method of preventing unauthorized use of broadcast content.
The afore-mentioned U.S. patent application Ser. No. 09/388,926 describes a system wherein a prepaid music card is used to decipher broadcast programs received substantially in real-time. In other words, a receiver is operable to buffer a selected amount of a program (e.g., the first two minutes of program reception). If the receiver determines that the beginning of the program has been captured in the buffer, the receiver proceeds to transfer the remainder of the received program to a storage device once the user has indicated that storage of the received program is desired. If the received program is encrypted, the music card is then debited when the received and stored program is decrypted and provided to a portable storage medium.
As stated previously, much of the audio program content transmitted in a broadcast signal is transmitted on a substantially repetitive basis (e.g., popular songs on play lists for repeat broadcast transmission throughout the day). As disclosed in the afore-mentioned U.S. patent application Ser. No. 09/695,226, such content can be stored locally with respect to the receiver to allow more efficient use of system bandwidth. In other words, the broadcast signal comprises an index for retrieving a locally stored audio program at a receiver, in lieu of providing the entire audio program in the broadcast signal. A need also exists for a digital broadcast system employing local storage of selected content at receivers which allows users to purchase and decrypt any of the locally stored content that is encrypted, and to store the decrypted content onto a portable storage medium.
The above described disadvantages are overcome and a number of advantages are realized by a digital broadcast system wherein receivers are provided with local storage devices for storing selected content (e.g., audio programs). The receivers are configured to receive the broadcast signal and to generate an output signal for playback via a loudspeaker, for example, using content transmitted in the broadcast signal or by accessing and retrieving from said local storage device previously stored content segments that were identified in the broadcast signal.
In accordance with another aspect of the present invention, receivers are provided with means for connecting to a distribution center via a reverse channel to obtain authorization to decrypt selected stored content. The receivers are configured to allow users to indicate when content transmitted in or identified in the broadcast signal are desired to be purchased, decrypted and downloaded to a portable storage medium.